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What are rocks? Do you remember what forms rocks? Atoms form Elements …. that form…. that form.... that form…. that form….. Classification of Rocks •The grouping of objects that have things in common is called classification. •Rocks are classified by the way they form. •Petrologists classify rocks and .

Classes of rocks

•Igneous Rocks •Sedimentary Rocks •Metamorphic Rocks

Igneous Rocks • Igneous means “Formed by fire”. • Formed as rises through cracks in the Earth’s crust. • The cooled magma crystallizes and hardens. • Igneous is then formed! • Makes up 75% of Earth’s crust. Review!! What is magma? Molten rock inside the Earth. What is lava? Molten rock on Earth’s surface. Which layer of the Earth contains magma? Mantle or asthenosphere Classifying

Scientists classify igneous rock according to where it is formed -- above the Earth’s surface or below the surface. The two types of igneous rocks are intrusive and extrusive. What is the difference between intrusive and extrusive igneous rock?

Intrusive rock form under the Earth’s surface. Extrusive above the surface. Explore!! Examine the samples of these igneous rocks. Identify whether the following are intrusive or extrusive. Pumice Rhyolite Obsidian Scoria All rocks begin as igneous rocks. • Igneous rock must be broken down in order to form sedimentary rock. • How does this occur Sedimentary Rock Now that rocks are broken down into sediments, sedimentary rock may form. Two ways for this type of rock to form: 1) Formed in water from accumulated sediments. 2) Formed from remains of living things. Two groups of Sedimentary Rock

• Clastic: Formed from fragments caused by erosion and transported by water, wind, or ice. (Conglomerates, sandstone, shale) • Nonclastic: Made up of dissolved minerals or the remains of plants and animals. (Fossils, cave stalactites and stalagmites, limestone) Explore!! Examine the samples of sedimentary rocks. Identify whether they are clastic or nonclastic. I have jars of HCl acid (diluted) that you can test for calcium carbonate … nonclastic. Record qualitative and quantitative data. Oil Shale (1) Gray Shale (2) Gray Sandstone (3) Fossil Limestone (4) Fine Limestone (5) Banded Sandstone (6) Conglomerate (7) • Metamorphic rocks are chemically changed rocks. • The heat and pressure inside the Earth “bakes” and changes the minerals inside rocks. • The Earth’s oven can change igneous, sedimentary, or even metamorphic rocks into other metamorphic rocks. How are metamorphic rocks classified? • Foliated: Minerals are arranged in bands. (Granite  gneiss, Shale, basalt, or granite  , Shale  slate) • Nonfoliated: Minerals are not arranged in bands. (Limestone  marble, Sandstone  quartzite) Explore!! Examine the samples of metamorphic rocks. Identify whether they are foliated or nonfoliated. Record qualitative and quantitative data. Quartzite (1) Gneiss (2) Mica Schist (3) Chlorite Schist (4) Marble (5) Gray Sandstone (Sedimentary) (6) Limestone (7)